Java DES文件加密解密 javax.crypto.BadPaddingException: Given final block not properly padded

本工具类经过测试可用，之前写的没有使用CipherInputStream和CipherOutputStream，生成的加密文件与源文件大小不一致，加密时没有问题，解密时总是抛出如下异常：

Exception in thread "main" javax.crypto.BadPaddingException: Given final block not properly padded     at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)     at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)     at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)     at javax.crypto.Cipher.doFinal(DashoA13*..)

其中BASE64底层依赖库没有使用SUN的，而是下载的“javabase64-1.3.1.jar”
DESUtils.java

package demo.security;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.Key;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

/**
 * <p>
 * DES加密解密工具包
 * </p>
 * 
 * @author IceWee
 * @date 2012-5-19
 * @version 1.0
 */
public class DESUtils {
    
    private static final String ALGORITHM = "DES";
    private static final int CACHE_SIZE = 1024;

    /**
     * <p>
     * 生成随机密钥
     * </p>
     * 
     * @return
     * @throws Exception
     */
    public static String getSecretKey() throws Exception {
        return getSecretKey(null);
    }
    
    /**
     * <p>
     * 生成密钥
     * </p>
     * 
     * @param seed 密钥种子
     * @return
     * @throws Exception
     */
    public static String getSecretKey(String seed) throws Exception {
        SecureRandom secureRandom;
        if (seed != null && !"".equals(seed))
            secureRandom = new SecureRandom(seed.getBytes());
        else
            secureRandom = new SecureRandom();
        KeyGenerator keyGenerator = KeyGenerator.getInstance(ALGORITHM);
        keyGenerator.init(secureRandom);
        SecretKey secretKey = keyGenerator.generateKey();
        return Base64Utils.encode(secretKey.getEncoded());
    }
    
    /**
     * <p>
     * 加密
     * </p>
     * 
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encrypt(byte[] data, String key) throws Exception {
        Key k = toKey(Base64Utils.decode(key));
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, k);
        return cipher.doFinal(data);
    }
    
    /**
     * <p>
     * 文件加密
     * </p>
     * 
     * @param key
     * @param sourceFilePath
     * @param destFilePath
     * @throws Exception
     */
    public static void encryptFile(String key, String sourceFilePath, String destFilePath) throws Exception {
        File sourceFile = new File(sourceFilePath);
        File destFile = new File(destFilePath); 
        if (sourceFile.exists() && sourceFile.isFile()) {
            if (!destFile.getParentFile().exists()) {
                destFile.getParentFile().mkdirs();
            }
            destFile.createNewFile();
            InputStream in = new FileInputStream(sourceFile);
            OutputStream out = new FileOutputStream(destFile);
            Key k = toKey(Base64Utils.decode(key));
            Cipher cipher = Cipher.getInstance(ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, k);
            CipherInputStream cin = new CipherInputStream(in, cipher);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = cin.read(cache)) != -1) {
                out.write(cache, 0, nRead);
                out.flush();
            }
            out.close();
            cin.close();
            in.close();
        }
    }
    
    /**
     * <p>
     * 解密
     * </p>
     * 
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] decrypt(byte[] data, String key) throws Exception {
        Key k = toKey(Base64Utils.decode(key));
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, k);
        return cipher.doFinal(data);
    }
    
    /**
     * <p>
     * 文件解密
     * </p>
     * 
     * @param key
     * @param sourceFilePath
     * @param destFilePath
     * @throws Exception
     */
    public static void decryptFile(String key, String sourceFilePath, String destFilePath) throws Exception {
        File sourceFile = new File(sourceFilePath);
        File destFile = new File(destFilePath); 
        if (sourceFile.exists() && sourceFile.isFile()) {
            if (!destFile.getParentFile().exists()) {
                destFile.getParentFile().mkdirs();
            }
            destFile.createNewFile();
            InputStream in = new FileInputStream(sourceFile);
            OutputStream out = new FileOutputStream(destFile);
            Key k = toKey(Base64Utils.decode(key));
            Cipher cipher = Cipher.getInstance(ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, k);
            CipherOutputStream cout = new CipherOutputStream(out, cipher);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = in.read(cache)) != -1) {
                cout.write(cache, 0, nRead);
                cout.flush();
            }
            cout.close();
            out.close();
            in.close();
        }
    }

    /**
     * <p>
     * 转换密钥
     * </p>
     * 
     * @param key
     * @return
     * @throws Exception
     */
    private static Key toKey(byte[] key) throws Exception {
        DESKeySpec dks = new DESKeySpec(key);
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
        SecretKey secretKey = keyFactory.generateSecret(dks);
        return secretKey;
    }
    
}

 

Base64Utils.java

package demo.security;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

import it.sauronsoftware.base64.Base64;

/**
 * <p>
 * BASE64编码解码工具包
 * </p>
 * <p>
 * 依赖javabase64-1.3.1.jar
 * </p>
 * 
 * @author IceWee
 * @date 2012-5-19
 * @version 1.0
 */
public class Base64Utils {

    /**
     * 文件读取缓冲区大小
     */
    private static final int CACHE_SIZE = 1024;
    
    /**
     * <p>
     * BASE64字符串解码为二进制数据
     * </p>
     * 
     * @param base64
     * @return
     * @throws Exception
     */
    public static byte[] decode(String base64) throws Exception {
        return Base64.decode(base64.getBytes());
    }
    
    /**
     * <p>
     * 二进制数据编码为BASE64字符串
     * </p>
     * 
     * @param bytes
     * @return
     * @throws Exception
     */
    public static String encode(byte[] bytes) throws Exception {
        return new String(Base64.encode(bytes));
    }
    
    /**
     * <p>
     * 将文件编码为BASE64字符串
     * </p>
     * <p>
     * 大文件慎用，可能会导致内存溢出
     * </p>
     * 
     * @param filePath 文件绝对路径
     * @return
     * @throws Exception
     */
    public static String encodeFile(String filePath) throws Exception {
        byte[] bytes = fileToByte(filePath);
        return encode(bytes);
    }
    
    /**
     * <p>
     * BASE64字符串转回文件
     * </p>
     * 
     * @param filePath 文件绝对路径
     * @param base64 编码字符串
     * @throws Exception
     */
    public static void decodeToFile(String filePath, String base64) throws Exception {
        byte[] bytes = decode(base64);
        byteArrayToFile(bytes, filePath);
    }
    
    /**
     * <p>
     * 文件转换为二进制数组
     * </p>
     * 
     * @param filePath 文件路径
     * @return
     * @throws Exception
     */
    public static byte[] fileToByte(String filePath) throws Exception {
        byte[] data = new byte[0];
        File file = new File(filePath);
        if (file.exists()) {
            FileInputStream in = new FileInputStream(file);
            ByteArrayOutputStream out = new ByteArrayOutputStream(2048);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = in.read(cache)) != -1) {
                out.write(cache, 0, nRead);
                out.flush();
            }
            out.close();
            in.close();
            data = out.toByteArray();
         }
        return data;
    }
    
    /**
     * <p>
     * 二进制数据写文件
     * </p>
     * 
     * @param bytes 二进制数据
     * @param filePath 文件生成目录
     */
    public static void byteArrayToFile(byte[] bytes, String filePath) throws Exception {
        InputStream in = new ByteArrayInputStream(bytes);   
        File destFile = new File(filePath);
        if (!destFile.getParentFile().exists()) {
            destFile.getParentFile().mkdirs();
        }
        destFile.createNewFile();
        OutputStream out = new FileOutputStream(destFile);
        byte[] cache = new byte[CACHE_SIZE];
        int nRead = 0;
        while ((nRead = in.read(cache)) != -1) {   
            out.write(cache, 0, nRead);
            out.flush();
        }
        out.close();
        in.close();
    }
    
    
}

 

DESTester.java

package demo.security;

public class DESTester {

    static String key;
    
    static {
        try {
 key = DESUtils.getSecretKey();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    public static void main(String[] args) throws Exception {
        long begin = System.currentTimeMillis();
        encryptFile();
        decryptFile();
        test();
        long end = System.currentTimeMillis();
        System.err.println("耗时：" + (end-begin)/1000 + "秒");
    }
    
    static void encryptFile() throws Exception {
        String sourceFilePath = "D:/demo.mp4";
        String destFilePath = "D:/demo_encrypted.mp4";
        DESUtils.encryptFile(key, sourceFilePath, destFilePath);
    }
    
    static void decryptFile() throws Exception {
        String sourceFilePath = "D:/demo_encrypted.mp4";
        String destFilePath = "D:/demo_decrypted.mp4";
        DESUtils.decryptFile(key, sourceFilePath, destFilePath);
    }
    
    static void test() throws Exception {
        String source = "这是一行测试DES加密/解密的文字，你看完也等于没看，是不是啊？！";
        System.err.println("原文:\t" + source);
        byte[] inputData = source.getBytes();
        inputData = DESUtils.encrypt(inputData, key);
        System.err.println("加密后:\t" + Base64Utils.encode(inputData));
        byte[] outputData = DESUtils.decrypt(inputData, key);
        String outputStr = new String(outputData);
        System.err.println("解密后:\t" + outputStr);
    }

}